Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer death and is driven mostly by mutated Kras gene. Despite advances in our understanding of the pathogenesis of PDAC, the disease remains highly refractory to treatment. In this proposal, we will employ genome scale approaches to identify potential signaling nodes and druggable targets that will be used for therapeutics development for PDAC patients. Based on our preliminary data and technical capabilities, we proposed the following specific aims. Aim #1) To identify co-extinction targets for combination therapeutics against KRAS* PDAC. The goal of this aim is to identify candidate targets that when co-extinguished can lead to suppression or death of KRAS* PDAC tumor cells. Both genetic and pharmacological approaches will be used, taking advantage of strengths of both mouse and human systems, as well as leveraging the emerging comprehensive genomic data on human PDAC. Co-extinction target candidates identified in more than one system will be prioritized for in-depth biological, functional as well as clinical pathological validation. Aim #2) To identify resistance mechanism to KRas inhibition. The goal of this aim is to proactively anticipate and elucidate possible molecular basis for resistance in setting of Kras* inhibition. We will apply a novel in vivo context-specific genetic screen approach to identify and functionally validate genes that promote survival of PDAC cells following KRas inactivation, initially focusing on the kinases followed by genetic elements of interests defined by comprehensive genomics by ICGC PDAC project. Furthermore, we will engineer GEM models with the most promising resistant hits to validate resistance mechanism in vivo and to test new therapeutic strategy against such resistance mechanisms.